Reconfiguring Heart Features

ABSTRACT

Among other things, a heart tissue support has gripping elements, each element having a free end that is sharp enough to penetrate heart tissue when pushed against the tissue, and a feature to resist withdrawal from the tissue after the sharp free end has penetrated the tissue. Among other things, the shape of a heart valve annulus is corrected in a catheter laboratory by orienting a tip of a catheter holding a heart tissue support that has gripping elements at the valve annulus, applying a radial force from the catheter against the annulus by opening a structure at the tip of the catheter, and while the structure is opened, forcing the support onto the annulus. Among other things, the shape of a heart valve annulus is corrected during a surgical procedure by pushing a heart tissue support that has gripping elements onto the annulus.

This is a continuation-in-part of U.S. patent application Ser. No.11/620,955, filed on Jan. 8, 2007, which is incorporated herein in itsentirety by reference.

BACKGROUND

This description relates to reconfiguring heart features.

The annulus of a heart valve (a fibrous ring attached to the wall of theheart), for example, maintains the shape of the valve opening andsupports the valve leaflets. In a healthy heart, the annulus istypically round and has a diameter that enables the leaflets to closethe valve tightly, ensuring no blood regurgitation during contraction ofthe heart. Because the annulus of the tricuspid valve, for example, issupported more stably by the heart tissue on one side of the annulusthan on the other side, and for other reasons, the size and shape of theannulus may become distorted over time. The distortion may prevent thevalve from closing properly, allowing blood to regurgitate backwardsthrough the valve. The distortion can be corrected, for example, duringopen heart surgery, by attaching a ring or other support around theannulus to restore its shape and size.

SUMMARY

In general, in an aspect, a heart tissue support has gripping elements,each gripping element having a free end that is sharp enough topenetrate heart tissue when pushed against the tissue, and a feature toresist withdrawal of the gripping element from the tissue after thesharp free end has penetrated the tissue.

Implementations may include one or more of the following features. Thefree ends of the gripping elements may project away from a surface ofthe support. The feature that resists withdrawal of the gripping elementfrom the tissue may comprise a finger projecting laterally from thegripping element. The heart tissue support may comprise an annularsurface bearing the gripping elements. The support may be expandable andcontractible. The support may have a native size that is configurable. Awire may configure the native size. The support may comprise at leastone of stainless steel, gold, Nitinol, or a biologically compatibleelastomer. The support may comprise a torus. The support may comprise ahelically wound portion. Some portions of the support may bear nogripping elements. The gripping elements may be organized in a pattern.The pattern may comprise rows. The pattern may comprise a group in whichthe gripping elements are more densely placed and a group in which thegripping elements are less densely placed. The pattern may comprisearcs. The pattern may comprise clusters. The pattern may comprise randomplacement. At least some of the gripping elements may comprise at leastone of platinum, gold, palladium, rhenium, tantalum, tungsten,molybdenum, nickel, cobalt, stainless steel, Nitinol, and alloys of anycombination of them. The gripping elements may have the same size. Someof the gripping elements may be of different sizes. At least some of thegripping elements may have more than one of the feature that resistswithdrawal. At least some of the gripping elements may project from thesurface orthogonally. At least some of the gripping elements may becurved. The heart tissue support may also include a sleeve through whichtissue can grow. The sleeve may comprise polyethylene terephthalate.There may be between about 15 and a million gripping elements on thesupport. There may be between about 100 and about 100,000 grippingelements. The gripping elements may comprise burr hooks. The grippingelements may comprise arrows. The gripping elements may comprise hooks.

In general, in an aspect, the shape of a heart valve annulus iscorrected in a catheter laboratory by orienting a tip of a catheterholding a heart tissue support that has gripping elements at the valveannulus, applying a radial force from the catheter against the annulusby opening a structure at the tip of the catheter, and while thestructure is opened, forcing the support onto the valve annulus.

In general, in an aspect, the shape of a heart valve annulus iscorrected during a surgical procedure by pushing a heart tissue supportthat has gripping elements onto the valve annulus.

In general, in an aspect, a method comprises attaching, to differentsized heart valve annuli in different patients, supports that can beexpanded in preparation for attachment and allowed to contract to acommon relaxed, non-expanded native size when they are in place on theannuli, and reducing the sizes of at least some of the in-place supportsto be smaller than the common relaxed non-expanded native size, toaccommodate the different sized heart valve annuli of differentpatients.

In general, in an aspect, a heart tissue support comprises a largenumber of small grippers, each having a tissue penetration feature and aretention feature, and the configuration of the grippers relative to aconfiguration of a given area of heart tissue to which the support is tobe attached by force being such that the penetration features of afailed set of the grippers will fail to penetrate the tissue, thepenetration features of a second set of the grippers will successfullypenetrate the tissue, the retention features of a subset of the secondset of grippers will fail to retain the grippers in the tissue, and theretention features of the remaining grippers of the second set willsuccessfully retain the grippers in the tissue and hold the support inan intended configuration on the tissue.

In general, in an aspect, a method comprises pushing a support onto aregion of heart tissue to cause only a portion of a number of smallgrippers on the support to embed themselves and be retained in thetissue, the portion being sufficient to attach the support securely tothe heart tissue.

In general, in an aspect, an annular heart valve support is expandableand contractible and bears gripping elements configured to penetrateheart tissue and to retain the elements in the tissue after penetration.

In general, in an aspect, a tool to attach a support to a heart valveannulus comprises mechanisms to hold the support in an expandedconfiguration prior to attachment, to expand the heart valve annulusprior to attachment, to enable the attachment of the support in itsexpanded configuration to the expanded valve annulus, and to release theexpanded support to a contracted configuration after the attachment.

Implementations may include one or more of the following features. Thetool may be attached to an end of a catheter. The tool may also comprisean inflatable balloon. The balloon may play a role in positioning thetool. The mechanisms may also be to remove the tool from the heart afterattachment.

In general, in an aspect, tool to attach a support to a heart valveannulus comprises a structure to expand the annulus of the heart to apredetermined shape under control of an operator.

Implementations may include one or more of the following features. Thestructure of the tool may have a conical outer surface at least aportion of which conforms to the predetermined shape. The structure ofthe tool may have an outer surface that can be expanded to thepredetermined shape.

Among advantages of these and other aspects and features are one or moreof the following. The operator need not work as slowly in order tocorrectly attach the heart tissue support to the annulus, nor doesplacement require as much precision. Not all of the burr hooks orgrippers need be attached to the annulus to keep the support in place.Some of the burr hooks or grippers might fail to grab onto tissue, or bepulled away from tissue by force. Nonetheless, as long as a minimumthreshold percentage of the burr hooks or grippers remain in place, sowill the tissue support. Further, because of its ease and simplicity,this procedure can be done in a catheterization laboratory, as well asin surgery.

These and other aspects and features, and combinations of them, may beexpressed as apparatus, methods, systems, and in other ways.

Other features and advantages will be apparent from the description andthe claims.

DESCRIPTION

FIGS. 1A through 1H and 13A through 13D show delivery of a heart valvesupport.

FIGS. 2A through 2D are perspective views of a heart valve support.

FIG. 2E is a plan view of a recurved hook.

FIG. 3 is a section side view of a heart valve support.

FIGS. 4A through 4C are side and detailed views of a delivery tool andheart valve support.

FIG. 5 is a side view of a delivery tool.

FIGS. 6A and 6B are sectional side views of a catheter delivery tool.

FIGS. 7A through 8I show delivery of a heart valve support.

FIGS. 9A, 9R, 9T and 9U are plan views of a heart tissue support.

FIGS. 9B, 9P, and 9S are perspective views of fragments of heart tissuesupports.

FIGS. 9C through 9E, 9G and 9H are side views of burr hooks.

FIG. 9F is a schematic view of a heart tissue support attached toannular tissue.

FIGS. 9I through 9M and 9O are close-up views of portions of hearttissue support surfaces.

FIGS. 9N and 9Q are views of a heart tissue support and a delivery tool.

FIGS. 10A and 10B are side views of a delivery tool, and a cross-sectionof a sheath.

FIGS. 10C and 10D are cross-sectional views of a delivery tool andsheath.

FIG. 11A is a perspective view of a delivery tool in a heart annulus.

FIG. 11B is a view of the operator end of a delivery tool.

FIGS. 11C and 11F are close-up views of a heart tissue support attachedto a delivery tool.

FIGS. 11D and 11E are close-up views of a portion of a heart tissuesupport attached to annular tissue.

FIGS. 12A and 12B are views of a core of a delivery tool.

FIG. 12C is a perspective view of a core of a delivery tool.

As shown in the examples of FIGS. 1A through 1G distortion of an annulus18 of a heart valve 16 can be corrected simply and quickly by thefollowing steps:

A. Push 201 (FIG. 1A) a conical head-end basket 220 of a delivery tool200 into the valve to force the distorted annulus (203, FIG. 1F) toconform to a desired configuration (e.g., a circle 205, FIG. 1G) and toa size that is larger (e.g., in diameter 207) than a desired finaldiameter 209 of the annulus (FIG. 1H). (The tool including the basketare shown in side view and the valve and annulus are shown in sectionalside view.)

B. Continue to push 201 the delivery tool to drive an expanded heartvalve support 100 (which has the desired configuration and the largersize and is temporarily held in its expanded configuration on the basketof the tool) towards the annulus to seat multiple (for example, eight,as shown, or a larger or smaller number of) recurved hooks 120 locatedalong the periphery of the support simultaneously into the valve tissueat multiple locations along the periphery 121 of the annulus (FIG. 1B).

C. After the hooks are seated, pull 204 (FIG. 1C) on and evert the tip230 of the head end basket from the inside to cause the support to rollso that the tips 122 of the hooks rotate 211 and embed themselves moresecurely into the annulus tissue (FIG. 1C).

D. After the hooks are further embedded, continue to pull 204 (FIG. 1D)on the inside 213 of the tip of the head-end basket to break the toolaway from the support (FIG. 1E), allowing the support to contract to itsfinal size and shape 215 (FIG. 1H) and leaving the support permanentlyin place to maintain the annulus in the desired final configuration andsize.

The entire procedure can be performed in less than a minute in manycases. By temporarily forcing the annulus of the valve to expand to thedesired circular shape, it is possible to attach the support quickly,easily, and somewhat automatically by forcing multiple gripping elementsinto the tissue at one time. Hooks are used in this example, althoughother types of gripping elements may be used as well. The physicianavoids the time consuming steps of having to attach individual suturesor clips one at a time along the periphery of a distorted annulus andthen cinch them together to reform the supported annulus to a desiredshape and size. Thus, the physician does not even need to be able to seethe annulus clearly (or at all). Once attached, when the tool isremoved, the support automatically springs back to its final shape andsize.

As shown in FIGS. 2A and 2D, in some implementations the supportincludes a circular ring body 110 that bears the hooks 120. The body 110can be expanded from (a) a minimal-diameter long-term configuration(FIG. 2A) to which it conforms after it has been attached to the annulusto (b) an expanded delivery configuration (FIG. 2D) to which it conformswhen it is held on the head-end basket of the tool and while it is beingattached in the steps shown in FIGS. 1A, 1B, and 1C. The long-termconfiguration is normally circular and has the diameter of a healthyannulus for a particular patient. When attached, the support maintainsthe healthy configuration of the annulus so that the valve will workproperly.

In some examples, the body 110 has the same (e.g., circular) shape butdifferent diameters in the delivery configuration and the long-termconfiguration. The body is constructed of a material or in a manner thatbiases the body to contract to the long-term configuration. For example,all or portions of the body 110 may be formed as a helical spring 110 asuch as a continuous helical spring connected at opposite ends to form acircular body or one or more interconnected helical spring segments(FIG. 2B). In some examples, the support body 110 b may be a band ofshape memory material such as Nitinol or a biologically compatibleelastomer (or other material) that will return to the long-termconfiguration after being expanded to the delivery configuration (FIG.2C).

The hooks 120 may number as few as three or as many as ten or twenty ormore and may be arranged at equal intervals along the body or at unequalintervals as needed to make the body easy and quick to deliver,permanent in its placement, and effective in correcting distortion ofthe valve annulus. The hooks are configured and together mounted alongthe circular outer periphery so that they can be inserted simultaneouslyinto the tissue along the periphery of the annulus and then firmlyembedded when the tool is pulled away and the basket is everted.

In some examples, a portion or portions of the support body may not havehooks attached if, for example, a segment of the valve annulus shares aboundary with sensitive or delicate tissue, such as the atrioventricular(AV) node of the heart. This tissue should not be pierced by the hooks.A support body configured to avoid interfering with the AV node couldhave a section having no hooks attached or otherwise covered orprotected to prevent penetration by hooks into the AV node. The supportbody should be positioned so that this special section of the supportbody is adjacent the sensitive or delicate tissue as the support body isput into place. The support body may have more than one special sectionlacking hooks, so that the operator has more than one option whenplacing the support body near the sensitive tissue. In some examples,the support body could have a section removed entirely, and would beshaped somewhat like the letter “C” instead of a complete ring. In anyof these examples, the procedure described above could have anadditional step preceding step A, in which the operator rotates thedelivery head to position the section having no hooks or to position thegap in the support body to be adjacent to the sensitive tissue at themoment when the hooks are to be embedded in the other tissue. Thesupport body may have radiopaque marks to help the operator view thepositioning.

For this reason, as shown in FIG. 2E, for example, each of the hooks hastwo pointed features. One pointed feature is a sharp free end 122pointing away from the valve leaflets during delivery. The other pointedfeature is a barb 128 formed at a bend between the sharp free end 122and an opposite connection end 124 where the hook is attached, e.g.,welded or glued, to the body 110. The barb points toward the valveleaflets during delivery. Thus, the barb is arranged to penetrate thetissue when the tool is pushed toward the valve, and the sharp free endis arranged to embed the hook into the tissue when the tool is pulledaway from the valve.

Each hook 120 can be formed of biologically compatible materials such asplatinum, gold, palladium, rhenium, tantalum, tungsten, molybdenum,nickel, cobalt, stainless steel, Nitinol, and alloys, polymers, or othermaterials. During delivery the barbs of the hooks are together (and moreor less simultaneously) forced into the tissue at a series of locationsaround the outer periphery of the temporarily expanded annulus. In alater step, the sharp free ends are forced to rotate somewhat away fromthe leaflets for secure (e.g., permanent) attachment.

To cause the hooks to rotate during delivery, the hooks 120 are attachedpermanently to the support body 110 and the support body can be rolled123 (FIG. 3) about a central annular axis 112 of the support body, asindicated. One way to cause the rolling of the support body and theassociated rotation of the hooks is to enable the body to change itsconfiguration by rotation of the entire body about an axis representedby the central circular axis 123, much as a rubber o-ring can be rolledabout its central circular axis. The reconfiguration of the body tocause the rotation of the hooks can be achieved in other ways.

In some examples, applying an axial force (arrows 113) to the innerperipheral edge of the ring (we sometimes refer to the support broadlyas a ring) will cause the ring to tend to roll and the hooks to embedthemselves in the annulus as intended. By appropriately mounting theinner periphery of the ring on the outer periphery of the delivery tool,the axial force 113 can be applied by pulling the tool away from theleaflets of the valve, as explained earlier.

For delivery to the valve annulus, the valve support 100 is firstexpanded to its delivery configuration and temporarily mounted on adelivery head 220 of the tool 200 (FIG. 4A). The support could beexpanded enough in its temporary mounting on the tool and mounted farenough away from the tip along the conical head-end basket so that whenthe head-end basket of the tool is pushed against the annulus to forceit to expand to the size and shape of the expanded support, the annulusfirst has reached a circular, non-distorted shape before the supporthook barbs begin to penetrate the tissue. The tapered profile of thehead-end basket of the delivery tool allows the tool to accommodatesupports of various sizes. In some implementations, different shapes andsizes of baskets could be used for supports of different sizes.

The heart valve support 100 is held in place on the delivery head 220using one or more releasable connections 246. The connections 246 arearranged to translate forces from the tool 200 to the support 100 ineach of two opposite directions 248 and 250, toward or away from theleaflets of the valve. When the support has been embedded in the annulusand the tool is pulled in the direction 250 to release it from thesupport, the force on the connections 246 exceeds a predeterminedthreshold, and the connections break, releasing the tool from thesupport at the end of the delivery process. The connections 246 may be,in some examples, breakable sutures 252 (FIG. 4A), or some otherbreakaway structure such as clips or adhesive or a structure that can bemanipulated from the tool by unscrewing or other manipulation.

In some examples, the connections 246 include retainers that can take,e.g., the configurations shown as 254 a or 254 b (FIGS. 4B & 4C,respectively). In the example shown in FIG. 4B, the retaining element254 a has one rigid finger 256 to translate forces from the tool 200 tothe support 100 when the tool is moved in direction 248 while thesupport is attached to the tool and being pushed into the heart tissue.A second deformable finger 258 aids in maintaining the connectionbetween the support 100 and the tool 200 when the tool is moved indirection 250 and is deformable (dashed lines) to release the valvesupport 100 from the tool 200 when the force in direction 250 relativeto the embedded support exceeds a predetermined threshold.

In the example shown in FIG. 4C, the retaining element 254 b includes afinger 260 having a crook 262 to receive the support 100 and totranslate forces from the tool 200 to the support 100 when the tool ismoved in direction 248. The finger has a resiliently deformable tip 264that is biased towards the tapered body 222 and helps to maintain theconnection between the support 100 and the tool 200 and is deformable(shown in hidden lines) to release the valve support 100 from the tool200 when the tool is moved in the second axial direction 250 against anembedded support and the force exceeds a predetermined threshold.

As shown in FIG. 5, in an example of a tool 200 that can be used fordelivery of the support during open heart surgery, a basket 220 isconnected at its broad end to a set of stiff wires or other rigidprojections 216 that are splayed from a long shaft 210 having a handle212 at the operator's end 214. Thus the projections 216 connect theshaft 210 to the basket 220 and transfer pulling or pushing forcebetween the shaft and the basket (and in turn to the support).

The example of the basket shown in FIG. 5 includes a tapered body 222having a network of interconnected struts 224 defining an array ofopenings 226 together forming a tapered semi-rigid net. In this example,the basket (which we also sometimes refer to as a delivery head) 220 hasa rounded tip 228. The head 222 tapers radially outwardly with distancealong a longitudinal axis 234 of the head 220 from the tip 228 towardsthe operator. The broad end 232 of the tapered body 222 is firmlyattached to the projections 216, which taper in the opposite directionfrom the taper of the basket. The net formed by the struts 224 issemi-rigid in the sense of having enough stiffness to permit theoperator to force the valve support against the heart tissue to causethe barbs of the hooks of the support to penetrate the tissue, andenough flexibility to permit the head-end basket to be everted when theoperator pulls on the handle to evert the basket and release the supportfrom the basket.

In some implementations, the shaft 210 defines a lumen 236 extendingbetween the heart valve end 218 of the shaft 210 and the handle 212. Awire 238 is arranged to move freely back and forth within the lumen 236.The wire 238 has one end 240 that extends from the handle 212 and anopposite end 242 that is connected to the inside of tip 228. The wire238 can be pulled (arrow 244) to cause the delivery head 220 to collapse(hidden lines) and evert radially inwardly starting at the tip 228 asmentioned earlier.

Returning to a more detailed discussion of FIGS. 1A through 1E, theoperator begins the delivery of the support by pushing the tapered end230 of the head basket 220 into the valve 16 (e.g., the tricuspid valve)to cause the valve leaflets 14 to spread apart. The tip 230 is small androunded which makes it relatively easy to insert into the valve withoutrequiring very precise guidance. Because the head-end basket is tapered,by continuing to push, the operator can cause the annulus 18 of thetricuspid valve 16 to expand in size and to conform to a desired shape,typically circular. During insertion, because of its symmetrical taper,the head-end basket tends to be self-centering. The taper of the basket220 translates the insertion force in direction 248 into a radial forcethat causes the annulus 18 to expand and temporarily assume a desiredshape (and a larger than final diameter).

As the operator continues to push on the tool, the ring of barbs of thehooks touch and then enter (pierce) the heart tissue along a ring ofinsertion locations defined by the outer periphery of the annulus, andthe sharp free ends of the hooks enter and seat themselves within thetissue, much like fish hooks. Depending on how the operator guides thetool, the basket can be oriented during insertion so that essentiallyall of the hooks enter the tissue at the same time. Or the tool could betilted during insertion so that hooks on one side of the support enterthe tissue first and then the tool delivery angle could be shifted toforce other hooks into the tissue in sequence.

Generally, when the number of hooks is relatively small (say between 6and 20, comparable to the number of sutures that the physician would usein conventional stitching of a ring onto an annulus), it is desirable toassure that all of the hooks penetrate the tissue and are seatedproperly.

Once the hooks are embedded in the tissue, the operator pulls on thenear end 240 of wire 238 to cause the basket 220 to collapse, evert, andbe drawn out of the valve 16. Eventually, the everted portion of thebasket reaches the valve support 100. By further tugging, the operatorcauses the body 110 of the support 100 to roll about its central axis(as in the o-ring example mentioned earlier) which causes the hooks 120to embed more firmly in the tissue of the annulus 18 of the valve 16.

Using a final tug, the operator breaks the connections between the tool200 and the valve support 100 and removes the tool 200, leaving thevalve support 100 in place. As the everting basket 220 passes the pointsof connection 246, the retaining forces exerted by the embedded hooks120 of the support body 110, acting in direction 248, exceed the forcesexerted by the withdrawing basket 220 on the support body 110 (throughthe connections 246), acting in direction 250, thereby causing theconnections 246 to break or release, in turn releasing the support 100.

The tool 200 is then withdrawn, allowing the valve support 100, alongwith the annulus 18, to contract to the long-run configuration.

In implementations useful for delivery of the support percutaneously, asshown in FIG. 6A, the delivery head 220 a can be made, for example, froma shape memory alloy, such as Nitinol, which will allow the body 222 ato be collapsed radially toward the longitudinal axis 234 a prior to andduring delivery of the head from a percutaneous entry point (say thefemoral vein) into the heart. The delivery head 220 a is biased towardsthe expanded, tapered configuration shown in FIG. 6A. Thus, the deliveryhead 220 a, in the form of a tapered semi-rigid net, is connected to acatheter shaft 210 a through projections 216 a that splay radiallyoutwardly from the catheter shaft 210 a and taper in a directionopposite the taper of the delivery head 220 a. (Here we refer to thedelivery head as the head-end basket.)

The projections 216 a are resiliently mounted to the catheter shaft 210a and are biased towards the expanded, tapered orientation shown, forexample, by spring biased projections 216 b shown in FIG. 6B. Theprojections 216 a include springs 278, e.g., torsion springs (as shown),mounted to the catheter shaft 210 a and forming a resilient connection.

A wire 238 a slides within a lumen 236 a of the shaft 210 a in a mannersimilar to the one described earlier.

The tool 200 a also includes a sheath 280 in which the catheter shaft210 a can slide during placement of the support. The sheath 280, thecatheter shaft 210 a, and the wire 238 a are all flexible along theirlengths to allow the tool 200 a to be deflected and articulated along ablood vessel to reach the heart and to permit manipulation of thedelivery head once inside the heart.

To deliver the support percutaneously, as shown in FIG. 7A, when thedelivery head is prepared for use, the sheath 280 is retracted beyondthe projections 216 a, allowing the delivery head 220 a to expand. Thevalve support 100 is then expanded to the delivery configuration (eitherby hand or using an expansion tool) and mounted on the tapered body 222a. The valve support 100 is connected to the delivery head 220 a usingreleasable connections, e.g., breakable sutures and/or retainingelements (as described earlier).

The sheath 280 is then moved along the catheter shaft 210 a towards thedelivery head 220, causing the projections 216 a and the delivery head220 a to contract radially inwardly to fit within the sheath 280, asshown in FIG. 7B. In the contracted configuration, the tip 228 a of thedelivery head 220 a bears against the end 282 of the sheath 280. Therounded tip 228 a may, e.g., provide easier delivery and maneuverabilityin navigating the blood vessels to reach the heart.

To deliver the support to the valve annulus, the end 230 of the tool 200a is fed percutaneously through blood vessels and into the right atrium24 (FIG. 8A). The sheath 280 is then retracted, exposing the valvesupport 100 and allowing the projections 216 a, the delivery head 220 a,and the support 100 to expand, as shown in FIG. 8A.

In steps that are somewhat similar to the open heart placement of thesupport, the catheter shaft 210 a is then advanced, e.g., under imageguidance, in the direction 248 a along an axis 30 of the annulus 18. Theoperator forces the distal end 230 a of the self-centering delivery head220 a into the valve 16 (FIG. 8B) using feel or image guidance, withoutactually seeing the valve 16.

Once the tip is in the valve 16, the operator pushes on the end 214 a ofthe catheter shaft 210 a to force the tool further into the valve 16.This causes the tapered body 222 a of the delivery head 220 a to restorethe shape of the annulus 18 to a circle or other desired shape (such asthe distinctive “D” shape of a healthy mitral valve). The tool 200 atends to be self-centering because of its shape. The net-likeconstruction of the delivery head 220 a (and the head used in open heartsurgery, also) allows blood to flow through the valve even while thedelivery head 220 a is inserted.

As tool 200 a reaches the position at which the support hooks touch theannulus, by giving an additional push, the operator drives the hooks 120of the valve support 100 together into all of the annular locations atwhich it is to be attached, as shown in FIG. 8C. In some examples, itmay be possible for the operator to tilt the delivery head deliberatelyto cause some of the hooks to penetrate the tissue before other hooks.The configuration of the valve support 100 and the tool 200 a and themanner of temporary attachment of the support 100 to the tool 200 a tendto assure that the hooks 120 will penetrate the valve 16 at the correctpositions, just along the outer edge of the annulus 18.

Once the valve support 100 has been attached to the valve 16, theoperator pulls on the proximal end 240 a causing the delivery head 220 ato evert (hidden dashed lines) and be drawn out of the valve 16 (shownin FIG. 8D). Eventually the everted portion of the tool 200 a reachesthe valve support 100. By further tugging, the operator causes the torusof the support 100 to roll around its periphery which jams the free endsof the hooks 120 securely into the annulus 18 of the valve 16, asillustrated in FIG. 8E, seating the support permanently and permittinglater growth of tissue around the support 100. The depth and radialextent of each of the placed hooks 120 can be essentially the same as aconventional suture so that their placement is likely to be as effectiveand familiar to the operator and others as conventional sutures.

Using a final tug, the operator breaks the connections 246 between thetool 200 a and the valve support 100 and retracts the catheter shaft210, leaving the support 100 in place. The catheter shaft 210 isretracted to a position beyond the valve annulus 18 and the wire isadvanced in the first direction allowing the delivery head 220 a toassume its original tapered shape (FIG. 8F). The catheter shaft 210 a isthen refracted into the sheath 280 (FIG. 8G), and the tool 200 a iswithdrawn.

In some examples, as shown in FIGS. 8H and 8I, the tip 228 a of the tool200 a, when everted, has a compressed dimension that is smaller than aninternal diameter 284 of the sheath 280, permitting the catheter shaft210 a to be refracted directly into the sheath 280 after deployment,with the everted tip held within the collapsed delivery basket, as shownin FIG. 8I.

With the tool 200 a withdrawn, the valve support 100 contracts,reshaping the annulus 18 such that the valve leaflets 14 coapt toprevent a backflow of blood during systole.

Other implementations are within the scope of the claims.

For example, distortion of either the tricuspid valve or mitral valvecan be corrected. For tricuspid valve repair, the hooks can be arrangedaround only about three-quarters of the support and therefore theannulus. During the placement procedure, the operator will rotate thesupport to position the portion of the support having hooks. For mitralvalve repair, the hooks can cover the entire periphery of the annulus.In this scenario, the hooks are arranged around the full circumferenceof the support. Alternatively, the hooks can cover only the posteriorsection of the annulus of the mitral valve. In this scenario, the hookscan be arranged around two-thirds of the support. Similarly to thetricuspid valve example, the operator will position the portion of thesupport having hooks against the posterior section of the mitral valveannulus. Further, for mitral valve repair, a back-up valve can beprovided as part of the delivery tool to maintain heart function duringthe delivery procedure. Materials other than shape memory materials maybe used as the material for the support body, and other ways can be usedto force the support back to a desired size following expansion,including, for example, cross-bars that span the opening of the support.

In addition, the left atrial appendage of the heart can be closed by asimilar technique. For example, the tool can be pushed into an openingof an atrial appendage causing the opening to assume a predeterminedshape. The tool can continue to be pushed in order to embed the hooks ofthe expanded support into the periphery of the opening of the appendage.The tool can then be withdrawn, releasing the support, and allowing thesupport to contract. The support can have a relatively small contracteddiameter such that, when the tool is withdrawn, releasing the support,the support can contract to a relatively small size, effectively closingoff the appendage.

In addition to the open heart and percutaneous deployment procedures,the valve support can also be deployed through the chest.

The head-end of the tool need not be a basket, but can take any form,mechanical arrangement, and strength that enables the valve annulus tobe forced open to a shape that corresponds to the shape of the support.The basket can be made of a wide variety of materials. The basket can beheld and pushed using a wide variety of structural mechanisms thatpermit both pushing and pulling on the support both to seat and embedthe support in the annulus tissue and disconnect the support from thetool.

The tool need not be conical.

The support could take a wide variety of configurations, sizes, andshapes, and be made of a wide variety of materials.

The hooks could be replaced by other devices to seat and embed thesupport using the pushing force of the tool.

The hooks of the support need not be embedded directly in the annulusbut might be embedded in adjacent tissue, for example.

The support could take other forms and be attached in other ways.

In FIG. 9A, the support body 110 a can be a torus in the form of ahelical spring (as mentioned earlier). Such a support body can have anative circumference 116 on the order of ten centimeters in itscontracted state, and a proportional native diameter 114. Thecircumference can be selected based on the physical requirements of aparticular patient.

A close-up view of a fragment of this support body, FIG. 9B, shows thatsome implementations have a number (e.g., a large or very large number,for example, as few as say 15, or 100, and up to hundreds or eventhousands) of burr hooks 120 a attached to an outer surface 111 of thesupport body 110 a. In the example shown in FIG. 9B, the helical supportbody is wound from a flat strip that has the outer surface 111 and aninner surface 117. Although FIG. 9B shows the burr hooks attached onlyto the outside surface, burr hooks could also be attached to the innersurface for manufacturing reasons or for other purposes.

The burr hooks, which are small relative to the body, are eachconfigured to partially or fully pierce annular tissue when the part ofthe body to which the burr hook is attached is pushed against thetissue.

As shown in FIG. 9C, in some examples, each burr hook 120 a has a sharpfree end 122 a for piercing tissue and at least one barbed end 128 a,128 b (two are shown in FIG. 9C) for keeping the burr hooks embedded intissue. Each burr hook also has an end 124 a that is attached to thesurface of the support body. Once the support (we sometimes refer to thesupport structure simply as the support) is in contact with hearttissue, the embedded burr hooks hold the body in a proper position andconfiguration on the annulus. Burr hooks can be attached to the surfaceof the support body using glue, cement, or another type of adhesive, orformed from the support body as part of an industrial process, such asmolding, etching, die cutting, welding, or another process, or can beattached by a combination of these techniques. Different burr hooks on agiven support can be attached by different mechanisms.

Each burr hook 120 a can be structured and attached so that the free end122 a points in a direction 122 b perpendicular (or some other selectedeffective direction, or deliberately in random directions) to the bodysurface 111. In some cases, the burr hook can be curved. A barbed end128 a could be located on a concave edge 113 (FIG. 9D) or a convex edge115 (FIG. 9E) of a curved burr hook.

The burr hooks bear a resemblance to burr hooks on natural plant burrs.A different kind of attachment device could be used by analogy to metaltipped hunting arrows in which a sharp point has two broad and sharpshoulders that cut the tissue as the point enters. The tips of the twoshoulders serve a similar function to the barbs, keeping the arrowembedded once it enters the tissue.

In some implementations, the burr hooks on a support body have two ormore (in some cases, many) different shapes, sizes, orientations,materials, and configurations. By varying these features, for example,the orientations of the burr hooks, it may be more likely that at leastsome of the burr hooks will become embedded in the tissue, no matter howthe support body is oriented at the moment that it comes into contactwith the annulus. Varying the number, orientation, and curvature of thehooks may make it more likely that the support body will remain inplace. For example, in such a support, a force applied to the supportbody in a particular direction may unseat or partially unseat some ofthe burr hooks by disengaging the barbed ends from the tissue, but thesame force may not affect other burr hooks that have barbed endsoriented in a different direction or in a different configuration thanthe unseated burr hooks. The force applied to seat the support may causesome burr hooks to embed more securely than other burr hooks.

In use, typically not all of (in some cases not even a large portion of)the burr hooks will embed themselves in the tissue when the support bodyis pushed against the tissue, or remain embedded after placement. Asshown in FIG. 9F, there are enough burr hooks arranged in an appropriateway so only a fraction of the total hooks need be embedded in annulartissue (and in some cases only in certain regions) to create a physicalbond to keep the support body properly in place. The proportion of burrhooks on a support that need to embed securely in the tissue could rangefrom 1% to 10% or 40% or more. The averaging spacing of the successfullyembedded burr hooks could range from, say, one burr hook per millimeterof support body length to one burr hook per two or three or moremillimeters (or more) to secure the support appropriately. When burrhooks are grouped rather than arranged evenly on the support, thepercentages of and distances between successfully embedded hooks maydiffer.

When the burr hooks come into contact with the annular tissue duringdelivery, some 131, 133, but not necessarily all, of the burr hookspierce the tissue and (when a retracting force is applied to thedelivery tool) their barbs grip the tissue. Of the remaining burr hooks,some 135, 137 may (because of the contours of the tissue, for example)not even come into contact with the tissue, and others 139, 141 may notcome into contact with the tissue with sufficient force or in the rightorientation to pierce the tissue and have their barbs seat securely inthe tissue. Some of the burr hooks 143, 145 may penetrate the tissue butfail to grip the tissue. Some of the burr hooks 147, 149 may onlypenetrate the tissue at the barbed end 128 a, and not with respect tothe free end 122 a, providing a physical bond that may be weaker thanone in which the free end has been embedded in the tissue. For some ormany or most of the burr hooks that enter the tissue, however, thebarbed ends 128 a seat properly and resist forces in the direction 151that would otherwise unseat the burr hook. Even though a wrenching forceapplied to a particular burr hook in direction 151 could still be largeenough to unseat the barbed end, overall the combination of many burrhooks embedded in tissue tends to keep the support body set in place andin the proper configuration. Over time, some of the burr hooks that werenot embedded when the support was placed may become embedded, and someof the burr hooks that were embedded when the support was placed maybecome unseated.

The resistance provided by each of the barb or barbs to removal of agiven burr hook from the tissue may be relatively small. However, theaggregate resistance of the burr hooks that successfully embedthemselves will be higher and therefore can reliably keep the supportbody in place and the annulus of the valve in a desirable shape. Inaddition, because there are a number (potentially a very large number)of small burr hooks spread over a relatively large area, the stress onany part of the tissue of the annulus is quite small, which helps tokeep the support body properly seated and the valve shape properlymaintained along its entire periphery, all without damaging the tissue.The fact that a large number of burr hooks at close spacings may becomeembedded along the length of the support means that the support maybecome attached to the annulus more evenly and continuously than mightbe the case with the relatively smaller number of hooks describedearlier, and therefore perform better.

With respect to the implementations described beginning with FIG. 1A,the implementations shown beginning at FIG. 9A tend to have more andsmaller hooks not all of which need to become embedded successfully. Acommon concept between the two arrangements is that the hooks penetrateby being pushed into the tissue and have retaining elements that becomesecurely embedded in the tissue when a pulling force is applied at theend of the placement process. The two concepts are not mutuallyexclusive. Supports like those shown in FIG. 1A could also have burrhooks and supports like those shown in FIG. 9A could also have hooks ofthe kind shown in FIG. 1A. Placement of the support could rely on acombination of both kinds of hooks.

Each burr hook can be formed of a biologically compatible material suchas platinum, gold, palladium, rhenium, tantalum, tungsten, molybdenum,nickel, cobalt, stainless steel, Nitinol, and alloys, polymers, oranother material. As for the hooks shown beginning with FIG. 1A, thehooks can also be formed of a combination of such materials. Anindividual support body may exhibit burr hooks having a range ofcompositions. Some of the burr hooks attached to a support body may becomposed of one material or combination of materials, and some of theburr hooks may be composed another material or combination of materials.Each burr hook may be unique in composition. Further, some parts of aburr hook may be composed of one set of materials, and other parts maybe composed of another set of materials. In some examples, the region ofthe burr hook at the barbed end is composed of one set of materials,alloys, polymers, or mixtures, and the region of the burr hook at thefree end is composed of another set of materials, alloys, polymers, ormixtures, and the rest of the burr hook is composed of a further set ofmaterials, alloys, polymers, or mixtures. FIG. 9G shows an example burrhook that only has one barbed end 128 a. The burr hook extends from anattached end 124 a to a free end 122 a along the path of a principalaxis 920 that (in this case) is perpendicular to the support bodysurface 111. The barbed end spans a length 904 from the burr hook's freeend 122 a to the barbed end's free end 906. This free end 906 forms apoint spanning an acute angle 910 and the barbed end 128 a spans anacute angle 911 to grab the tissue in response to any force that wouldotherwise pull an embedded burr hook away from tissue.

The length 901 of each burr hook could be between about 1 and 12millimeters, as measured from the attached end 124 a to the free end 122a along the principal axis. Each barbed end could extend a distance 902from the burr hook lesser or greater than a principal width or diameter903 of the burr hook as measured at the attached end. The cross-sectionof the body of the burr hook could be flat or cylindrical or ovoid orany other of a wide variety of shapes.

Different burr hooks may be placed on the support body surface indifferent sizes and configurations. For example, different burr hooksmay have different lengths and different numbers and placement of barbedends. As shown in FIG. 9H, for example, a portion of support bodysurface 111 contains burr hooks 120 a that each have two barbed ends 128a, 128 b facing in a first direction 950 and shorter burr hooks 120 beach having one barbed end 128 a facing in a second direction 951. Also,the burr hooks may be arranged on the body surface in various densitiesand patterns of distribution. For example, as shown in FIG. 9I, the burrhooks may be placed on the surface of the body in repeating rows 930. Asshown in FIG. 9J, the burr hooks may be placed on the surface in rows ofdifferent lengths and densities 931, 932. As shown in FIG. 9K, the burrhooks may be placed on the surface along arc formations 933. As shown inFIG. 9L, the burr hooks may be placed on the surface as clusterformations 934. As shown in FIG. 9M, the burr hooks may be distributedrandomly 935. Other patterns may also be used.

A single support body can include a wide variety of patterns of burrhooks on its surface, because the physical characteristics of aparticular heart valve may mean that the valve tissue is either morereceptive or less receptive to a particular pattern of burr hookdistribution. Some patterns may be more effective on some types oftissue, and other patterns may be more effective on other types oftissue.

In addition, as shown in FIG. 9N, the burr hooks need not be present atthe points where the body 110 a contacts the delivery tool 220,including in the area near the rigid fingers 256, 258. This tends toprevent the burr hooks from causing the support body to stick to thetool.

As shown in FIG. 9O, any two burr hooks may be placed at a distance 905from each other greater than or less than the length 901, 901 a ofeither one.

As shown in FIG. 9P, when a support is formed helically, the ring can beconsidered to have a front side 961 (which faces the valve when thesupport is delivered), and a back side 960 that faces away from thevalve. In some examples, the support body 110 a does not have burr hooks120 a on the back side 960. In these implementations of the supportbody, the back side 960 is covered by a sleeve 963. After the supportbody has been attached to the annulus, the sleeve assists in thelong-term process of integration with valve tissue. Over a period oftime, heart tissue will attach to the support body as part of theprocess of healing. The sleeve is made of a material that allows thisprocess to occur faster than without the sleeve. For example, the sleevemay be composed of a porous material, which allows tissue to grow intothe sleeve, thus securing the support to the tissue more effectivelythan without the sleeve. The sleeve material may be a thermoplasticpolymer such as Dacron (polyethylene terephthalate). The sleeve materialmay alternatively be a metal or another type of material. The sleeve canbe placed on the support body at a location other than the back side.For example, the sleeve could be placed on the inner side 965 of thebody, with burr hooks remaining on the outer side 964.

The sleeve is formed as a half-torus in this example, but could have awide variety of other configurations. Such a sleeve may be used with anykind of support, including the one shown beginning in FIG. 1A, couldcover all or only part of the support, and could cover portions of thesupport that include hooks or barb hooks or both. In the latter case,the hook may be arranged to penetrate the sleeve during setup and beforethe support is placed into the heart. The sleeve could also cover aportion of the support meant to contact delicate or sensitive tissue,such as the AV node. In this case, the sleeve is made of a material thatis less likely to damage or interfere with the operation of the delicateor sensitive tissue, as compared to other materials that may be used inthe support.

Using burr hooks may make attaching the support faster, simpler, morereliable, and easier than for the larger hooks described earlier. Thedelivery tool operator may not need to apply as much force as might benecessary to embed larger hooks in the annular tissue. In some cases,the barbs would not need to be rotated as described for the larger hooksin order to embed them securely. The operator need not be concernedwhether all of the burr hooks have become embedded. Once the operatorhas determined that the support body has made contact with the tissueand by inference that many of the burr hooks have become attached, theoperator can tug on the support to confirm that it has been seated andthen release the support body from the delivery tool using one of themechanisms described earlier. Because of the ease of positioning, theprocedure could be performed easily in a non-surgical context, such asin a catheterization laboratory.

As shown in FIGS. 13A-13D, in the catheterization context, for aburr-hook support or any other kind of support being placed, thecatheter may include a balloon 228 b at the tip of the delivery tool.The balloon remains deflated as the catheter is passed through thepatient's blood vessels into the heart, as in FIG. 13A. When the tip ofthe catheter reaches the heart, the balloon can be inflated, shown inFIG. 13B. The inflated balloon floats in the blood being pumped throughthe heart and (along with the delivery tool) is carried easily and tosome extent automatically toward and into the valve that is to berepaired. The balloon can continue to move beyond the valve annulus,and, when located as shown in FIG. 13C, supports the distal end of thecatheter while the operator supports the proximal end of the catheter.The shaft of the catheter then serves as a “rail” supported at both endsand along which operations involving the delivery tool and the supportcan be performed with confidence that the rail is being held generallyon axis with the valve.

In some of the examples described earlier, the annulus of the heartvalve is expanded to the desired shape by pushing a conical surface,such as the basket, along the axis of and into the heart valve. Whetherthe delivery is done in the context of open heart surgery or in acatheterization lab, or elsewhere, the pushing of the conical surfaceinto the annulus can be supplemented by or replaced by a technique inwhich the expansion of the annulus is done after the delivery tool isinserted into the valve.

FIG. 9A shows one diameter of the support body, the native (long-termconfiguration) diameter 114. Recall that this diameter is different fromthe diameter in the delivery configuration. The former diameter 114 is,as shown in FIG. 9Q, smaller than the latter diameter 202 of thedelivery tool at the point of support body attachment 247. When thesupport body is placed on the delivery head 220, the coils of thehelical spring stretch outward as the body expands to fit on the tool.

During delivery, shown in FIGS. 13A-13D, when the support body has beenattached to the annulus 18, the operator releases the support from thedelivery tool. FIG. 13D shows that, in the absence of the outward forcepreviously applied by the delivery tool, the coils of the helical springcontract inwardly 1308 so that the support body returns to a finaldiameter 1309 of approximately its native diameter. Referring again toFIG. 1H, recall that because the annulus is attached to the supportbody, the support body will also pull the annulus inward, reforming theannulus to a desired smaller diameter 209.

If the support body is made of a material or alloy that is appropriatelyplastic, the support body may not fully contract to its original nativediameter. However, if the support body is made of a shape memory alloysuch as Nitinol, the memory effect of the alloy will tend to cause thesupport body to contract to a diameter nearly identical or identical toits original diameter.

As shown in FIG. 9R, the support body 110 a may have other portionsbearing no burr hooks. As mentioned earlier, sensitive or delicatetissue such as the AV node should not be punctured or bound to hooks. Insome examples, the support body 110 a can have a binding section 972having burr hooks and a non-binding section 974 having no burr hooks. Anon-binding section 974 of sufficient length to abut the AV node spansan angle 975 between about 40 and 60 degrees of the support bodycircumference. The binding section 972 will span an angle 973 of theremaining circumference. In some examples, a non-binding section 974 iscovered in a sleeve made of a material suited to contact the AV node orother sensitive tissue.

As shown in FIG. 9S, the two sections 972, 974 can have radiopaquemarkers 976, 977 indicating the borders between the two sections. Themarkers 976, 977 are each in the shape of an arrow pointing to thenon-binding section. During delivery, an operator can use the radiopaquemarkers 976, 977 to view the boundary of the non-binding section 974 andposition the non-binding section 974 against the AV node or othersensitive tissue.

As shown in FIG. 9T, the support body 110 a can have multiple sections974, 978 having no burr hooks. In some situations, the operator may belimited in the degree to which the delivery head can be rotated. In thisexample, the operator has multiple options for positioning the supportbody in order to avoid puncturing the AV node, and the operator wouldnot have to rotate the delivery head more than about 90 degrees in anydirection. Two non-binding sections are shown, but the support body canalso have three or more of these sections. The non-binding sections 974,978 span angles 975, 979 between about 40 and 60 degrees of the totalcircumference. In the example of two non-binding sections, there willalso be two binding sections 980, 982 spanning angles 981, 983 of theremaining two lengths of circumference.

As shown in FIG. 9U, the feature of the support body 110 a that shouldabut the AV node can take the form of an open section 990. As with thenon-binding section described above, the open section 990 may span anangle 995 between about 40 and 60 degrees of the circle defined by thesupport body 110 a, while the support body spans the remaining angle993. The open section 990 can also have radiopaque markers on the openends 992, 994 of the support body 110 a to assist an operator inpositioning the open section 990 against the AV node or other sensitivetissue.

As shown in FIGS. 10A-10D, the delivery head 220 can include a sheath280 a for covering the support body during insertion. FIGS. 10A and 10Bshow the sheath in a side section, and FIGS. 10C-10D show the sheath aswell as the delivery head in a cross-section at A-A in FIG. 10B. Thesheath 280 a wraps around the delivery head 220, including the supportbody 110 a, so that the burr hooks do not accidentally puncture orattach to any other tissue or devices prior to reaching the annulus. Thesheath is made of a flexible material, such as rubber, silicone rubber,latex, or another biologically compatible material or combination ofmaterials. The sheath can also be made of the same material or materialsas the catheter. Recall that one implementation of the sheath is shownin FIGS. 6A-6B and described in the corresponding text. Otherimplementations of the sheath are possible.

For example, the implementation of the sheath 280 a shown in sidesection in FIG. 10A is kept in place by attachment to an elasticretainer ring 1000 and a crossbar 1010 permanently affixed through andextending outward from the catheter shaft 210 perpendicular to thelongitudinal axis 234. The retainer ring 1000 is positioned closer tothe operator and farther from the distal end than is the support body110 a, and the crossbar 1010 is positioned farther from the operator andcloser to the distal end than is the support body. This sheath 280 a ispermanently attached 1002 to the retainer ring 1000. The sheath 280 a isalso attached to the crossbar temporarily at holes 1030, 1032 (visiblein FIG. 10B) sized to fit the projecting tips 1020, 1022 of the crossbar1010.

As shown in FIGS. 10B-10D, after insertion of the catheter into thevalve and when the delivery head 220 is expanded in preparation forattaching the support body 110 a, the combination of the retainer ringand crossbar allows the sheath to automatically detach from the crossbarand retract upward away from the support body as part of the expansionprocedure. The process by which this happens is as follows.

Referring to FIG. 10B, when the delivery head expands outward 1006, thediameter 1008 of the delivery head at the original point of retainerring attachment 1012 increases to a diameter greater than the diameter1009 of the retainer ring 1000. As a result, the retainer ring rollsupward 1004 from a point 1012 to a point 1005 on the delivery head ofsmaller diameter. As the retainer ring rolls, it pulls the distal end ofthe sheath in the same upward direction 1004 along the delivery head 220and away from the support body 110 a. Part of the sheath 280 a wrapsaround the ring as part of the rolling process; in a sense, the retainerring is “rolling up” the sheath, in the fashion of a scroll wrappingaround a roller. The retainer ring 1000 is rubber or anotherbiologically-compatible material with sufficient elasticity to allow thering to roll up the expanding delivery head.

When the delivery head 220 expands, the sheath 280 a is also releasedfrom the crossbar. A cross-section of the delivery head 220 includingthe crossbar 1010 is shown in FIG. 10C. When the delivery tool is intransit to a heart valve, the delivery head 220 is in the collapsedconfiguration. The sheath 280 a has holes 1030, 1032 configured to allowthe crossbar 1010 to pass through, holding the distal end of the sheathto the crossbar. Because the crossbar projects beyond the sheath, theends 1020, 1022 of the crossbar are rounded and smooth to prevent thecrossbar from piercing or tearing any tissue that it contacts before thedelivery head reaches its destination. Once the delivery head ispositioned near or inside a heart valve and begins expanding outward1006 from the shaft 210, the delivery head pushes the sheath 280 aoutward.

During the expansion process, as shown in FIG. 10D, the crossbar remainsin place and does not extend outward or change configuration, becausethe crossbar is permanently and securely attached to the shaft 210. As aresult, the delivery head pushes the sheath beyond the tips 1020, 1022of the crossbar, releasing the sheath from the crossbar. Thus, thesheath can move freely when the retainer ring rolls upward along thedelivery head, as described above. The crossbar 1010 may be made of anyof the materials used in the delivery tool, or anotherbiologically-compatible material, provided that the crossbar issufficiently rigid to keep the sheath 280 a in place, as described.

FIG. 11A shows another version of the delivery head 220 b. This versiondiffers slightly from the versions of the delivery head already shown.Specifically, in this version 220 b, the rigid projections 216 b arecomposed of an outer sleeve 1140 that encloses an inner arm 1142attached to the shaft 210 b by a hinge 1144. When this version of thedelivery head expands, the sleeve 1140 extends from the inner portion1142, and when the delivery head contracts, the sleeve withdraws alongthe length of the inner arm. This version of the delivery head is usedin FIG. 11A to demonstrate the use of a tightening wire 1100, but thistightening wire can be used with other versions of the delivery head aswell.

As shown in FIG. 11B, this tightening wire 1100 is threaded into andback out of a hole 1103 at the operator end 214 b of the delivery tool200 b. In doing so, the wire traverses the interior of the shaft 210 bof the delivery tool 200 b. The ends of the wire exterior to theoperator end 214 b form a loop 1102 to be manipulated by an operator.This wire 1100 can be used to activate a mechanism to adjust the shapeof the support body 110 a to a small degree, with the goal ofcontracting the final diameter 1309, an example of which is shown inFIG. 13B. Referring back to FIG. 11A, at the other end of the deliverytool 200 b, the wire exits the shaft 210 b at a hole 1105 placed at apoint above the delivery head 220 b. The wire extends down the side ofthe delivery head 220 b, guided by hoops 1120, 1122. As shown in FIG.11C, the wire is threaded along the interior of the helical coil 1150,1152 of the support. At the position 1164 where the wire has completed acircumference of the support body 110 a, the wire returns up the side ofthe delivery head and back into the shaft.

FIG. 11C also shows hoops 1124, 1126 that are placed on the struts 224 bof the delivery head at regular intervals to keep the wire properlypositioned. At the position 1164 where the wire meets itself and returnsup the side of the delivery head, spools 1130, 1132, 1134, 1136 attachedto the strut 224 b guide the wire and prevent the wire from scrapingagainst 1160, 1162 the helical loops 1150, 1152 at the wire exit region.The end of the wire that re-enters the hole 1105 (FIG. 11A) continuesback up the shaft alongside itself, and exits the delivery tool (FIG.11B) to form the loop 1102 by connecting with the other end.

When the support body 110 a is firmly seated at the heart valve annulus18 (for example, in the scenario shown in FIG. 13C), an operator canpull 1104 the loop 1102 (FIG. 11B) to reduce the final diameter of thesupport. When pulled, the wire tightens; as shown in FIG. 11C, thisbrings 1106 the coils 1150, 1152 of the support closer together.

The adjusted circumference becomes permanent as the burr hooks of thesupport embed themselves in the annular tissue. Although some burr hookswill already have been embedded, the tightening procedure will pull outsome of those burr hooks and embed other burr hooks in the tissue. This“bunches” annular tissue closer together. FIG. 11D shows an example of aportion of the support body 110 a attached to the periphery 121 of anannulus before the support body is tightened. As shown in FIG. 11E,after tightening, the support body 110 a pulls the tissue at theperiphery 121 closer together. The final diameter of the annulus will beslightly smaller due to this bunching effect. Once the delivery head isremoved, the support body, and thus the attached annulus, will contractto the desired size.

Referring to FIG. 11F, to detach the wire from the support body 110 a,the delivery head 220 b has a blade 1170 attached to one of the tworigid fingers 256 b, 258 b that keep the support body in place. When therigid finger 256 b pulls away from the support body 110 a after thesupport body is in place, the cutting segment 1172 of the bladestructure severs the wire. The operator may pull the external loop afterthe wire has been severed to keep the stray ends of the wire from movingfreely outside of the delivery tool when the tool is being removed fromthe annulus.

As shown in FIGS. 12A through 12C, a delivery tool 200 b for use in (butnot only in) a catheterization context shares elements in common withthe delivery tools discussed earlier, including the shaft 210 b,collapsible conical head end basket 220 b, set of struts 224 b, andoperator end 214 b. This delivery tool 200 b allows the operator toexpand or contract the collapsible conical head-end basket 220 bradially from a collapsed (closed) configuration (shown in FIG. 12A) toan expanded (open) configuration (shown in FIG. 12B), much in the waythat an umbrella can be opened. For this purpose the basket can includea set of spars 1210, 1212, 1214, 1216, 1218 arranged about the axis, asshown in FIG. 12C. Referring back to FIG. 12B, each spar has one hingedend 1220, 1222 connected to a central collar 1200 that can ride up 1202and down 1204 along a central shaft 1250 of the basket. Its other hingedend 1230, 1232 is connected to the hinged 1240, 1242 struts 224 b of thebasket in such a way that when the opening and closing mechanism ismanipulated 1208 by the user to cause the collar 1200 to move back andforth along the shaft 1250, the spars 1210, 1220 force 1206 the basketopen or closed, akin to the mechanism of an umbrella. The operator end214 b of the delivery tool has a twist or slide control 1150 thatenables the operator to control the collar. In FIG. 12B, the control isa slide control, and can be slid downward, for example. In this way, theannulus can be expanded to the desired shape by radial forces 1206 thatare not imposed by moving the entire basket linearly along the valveaxis. Instead the basket is moved into the desired position linearlyalong the valve axis and then the annulus is expanded to its desiredshape. The radial forces could also be imposed by a combination orsequence of moving the entire basket axially and expanding the basketlaterally.

As shown in FIG. 13A, radiopaque measurement marks 1310, 1312 can beplaced on the shaft or basket at regular spacings according to astandard measurement unit (e.g., one mark per centimeter). The marks canbe used to determine the distance that the delivery tool has traversedinside the heart and the location of the basket as it is inserted intothe valve, allowing the operator to place the basket at a good positionalong the axis of the valve.

The placement of the support from the basket onto the annulus can bedone either as part of the operation of opening the basket or followingthe opening of the basket. In the former case, illustrated in FIGS. 13Athrough 13D, the basket would be inserted into the valve to a pointwhere the basket is adjacent to the valve annulus. Simultaneously withthe opening of the basket, burr hooks on the outer periphery of thesupport would be forced radially into the annulus tissue. In this methodof placing the support, the porous sleeve described earlier and shown inFIG. 9P would be positioned on the inner periphery 965, away from theembedded hooks.

In the other approach, akin to the process shown in FIGS. 1A through 1D,the basket would be inserted into the valve so that the support on thebasket was positioned slightly upstream of the location of the annulus.The basket would then be opened to force the annulus into the desiredshape, then the tool and basket would be pushed slightly to force thesupport into place, embedding the hooks.

In either approach, once the support is placed, the basket would be atleast partially closed, releasing the basket from the support, and thetool would be withdrawn from the valve.

Further, in some implementations, a combination of the approaches couldbe used. For example, the basket could be partially opened, insertedinto the annulus, and then fully opened.

The approach of FIGS. 13A through 13D follows these steps:

A. Position 1301 (FIG. 13A) the collapsed (closed) conical head-endbasket 220 b of the delivery tool 200 b at the medial axis 30 of thevalve with the support adjacent the annulus. (The tool and basket areshown in side view and the valve and annulus are shown in sectional sideview.)

B. Press a button 1302 on the operator end 214 b to inflate a balloon228 b (FIG. 13B) on the distal end 230 b of the delivery tool, allowingthe delivery head 220 b to float into the correct position in the heartvalve 16. If necessary, rotate the delivery head to align any section ofthe support body not bearing burr hooks, or any gap in the support body,or any portion that is sheathed, with any section of the annulusabutting delicate or sensitive tissue.

C. Slide 1208 or twist the control 1150 to expand 1306 the basketbringing the support body 110 a into contact with the distorted annulus18. The support bears burr hooks that embed themselves in valve tissueat the periphery 121 of the annulus 18 upon contact, thus attaching thesupport to the tissue (FIG. 13C).

D. When the basket 220 b has reached a desired diameter 1303, theexpanded heart valve support 110 a forces the annulus 18 to conform to adesired configuration (e.g., a circle) and to a size that is larger(e.g., in diameter) than a desired final diameter of the annulus.Optionally, pull 1104 the wire loop 1102 to tighten the coils of thesupport body 110 a to achieve a smaller final diameter.

E. When the heart valve support is in its final position, to break thetool away from the support attachments 246 b, pull 1304 (FIG. 13D),allowing the support to contract 1308 to its final size (including finaldiameter 1309) and shape and leaving the support permanently in place tomaintain the annulus in the desired final configuration and size.Deflate 1311 the balloon 228 b by pressing the button on the operatorend.

1-36. (canceled)
 37. A tool to attach a support to a heart valveannulus, the tool comprising mechanisms to hold the support in anexpanded configuration prior to attachment, to expand the heart valveannulus prior to attachment, to enable the attachment of the support inits expanded configuration to the expanded valve annulus, and to releasethe expanded support to a contracted configuration after the attachment.38. The tool of claim 37 attached to an end of a catheter.
 39. The toolof claim 37 also comprising an inflatable balloon.
 40. The tool of claim39 in which the balloon plays a role in positioning the tool.
 41. Thetool of claim 37 also in which the mechanisms are also to remove thetool from the heart after attachment.
 42. A tool to attach a support toa heart valve annulus, the tool comprising a structure to expand theannulus of the heart to a predetermined shape under control of anoperator.
 43. The tool of claim 42 in which the structure has a conicalouter surface at least a portion of which conforms to the predeterminedshape.
 44. The tool of claim 42 in which the structure has an outersurface that can be expanded to the predetermined shape.
 45. The tool ofclaim 37 comprising a breakable connection between the tool and thesupport.
 46. The tool of claim 45 in which the connection comprises atleast one retaining element on an outer surface of the tool.
 47. Thetool of claim 42 comprising rigid projections that splayed from thestructure.
 48. A method of attaching a support to a heart valve annuluscomprising: holding the support in an expanded configuration prior toattachment, expanding the heart valve annulus prior to attachment,attaching the support in its expanded configuration to the expandedvalve annulus, and releasing the expanded support to a contractedconfiguration after the attachment.
 49. The method of claim 48 performedin a catheter laboratory.
 50. The method of claim 48 comprisinginflating a balloon.
 51. The method of claim 50 in which the balloonplays a role in positioning the support.
 52. The method of claim 48comprising breaking a breakable connection attached to the support. 53.A method of attaching a support to a heart valve annulus comprising:expanding a structure of a tool to expand the annulus of the heart to apredetermined shape under control of an operator.
 54. The method ofclaim 53 in which the structure has a conical outer surface at least aportion of which conforms to the predetermined shape.
 55. The method ofclaim 53 in which the structure has an outer surface that can beexpanded to the predetermined shape.
 56. The method of claim 53comprising causing rigid projections to splay from the structure.